Just what Dr Mark is saying isn't it? In fact I'd drop the 'or's and substitute 'and's. Perhaps these small muscle movements all act in concert. Raising the tongue leads to... Tensioning/compression of the lips leads to... Increased embouchure stiffness AND reduction of the aperture AND reduction in airflow AND increase in oral cavity pressure ALL leading to... A new system equilibrium frequency at the next partial up And vice versa Lowering the tongue leads to... Relaxation/decompression of the lips leads to... Reduced embouchure stiffness AND increase of the aperture AND increase in airflow AND reduction in oral cavity pressure ALL leading to... A new system equilibrium frequency at the next partial down. It seems from what some of top players are saying that tongue level is not vital for some but at least helpful for most in some circumstances. And this variation shouldn't be surprising: someone earlier on said something about skinning cats. I'd also be very surprised if oral cavity resonance didn't play some part too for some players at least. Raising the tongue will tend to reduce communication with the rest of the respiratory tract and encourage at least some higher resonant frequency vibrations which could conceivably help the process (if domesticated). Solar Bell posted something recently about Wynton claiming to use oral cavity resonance to assist his phenomenal tonguing speeds. Sounds quite reasonable. In short, it's probably futile to search for one single parameter to control pitch. It's a property of a complete functioning system. Like speed and noise are properties of VB's zen motorcycle. Remove the spark plugs and the speed and noise stop. That doesn't mean that the speed and noise are contained within the spark plugs.